FROM MATERIALS PHYSICS TO NANOSCALE DEVICES – 50 YEARS OF FINNISH RESEARCH IN SEMICONDUCTOR TECHNOLOGY Development of two important Finnish innovations: Humicap and ALD Tuomo Suntola Capacitive humidity sensor - Humicap Request to VTT Semiconductor laboratory by Vaisala Oy in 1971: “Development of a micro-sensor alternative for humidity measuring at weather stations and in radiosondes.” Pre-study by Tapio Wiik: Capacitive humidity sensors had been demonstrated with porous Al2O3 thin films and with polymer foil; Nylon foil humidity sensor was patented by Honeywell. The operational principle: Absorption of water vapor in a dielectric material result in an increase of the dielectric constant and the capacitance measured. Tuomo Suntola started the development with Anja Savolainen as laboratorian in December 1971. The polymer line was selected: Instead of using a self supporting foil, the polymer material was dissolved in a solvent and a polymer film was formed on a glass substrate using a spinner (like used for photoresist in the lab) or by drawing up the substrate uniformly from the polymer solution. Jorma Antson joined the team in late summer 1972, the development was completed by the end of 1973. Capacitance Capacitance Capacitive humidity sensor - Humicap Relative humidity (%) 0 50 + Nylon material was advantageous for having a low hysteresis. - The temperature and frequency dependence of the capacitance was substantial. 100 Relative humidity (%) 0 50 100 A specific polymer material with linear response and practically zero temperature dependence was found. With all polymers tested, the hysteresis was substantially lower in thin film structures than it was in self-supported foil structures. Capacitive humidity sensor - Humicap The thin film structure comprised - Very fast response - Large temperature range - Low temperature dependence - Suitable for mass production A prototype sensor made in 1973. The sensor was fully functional when photographed in 2014. Capacitive humidity sensor - Humicap As the world’s first thin-film capacitive humidity sensor, the HUMICAP® was a radical innovation that completely changed the way humidity is measured. The new groundhttp://www.vaisala.com/en/corporate/cases/Pages/humicapcelebratesits40years.aspx breaking technology had no moving parts, and it was amazingly small due to the advanced use of thin-film technology. Today, Vaisala is the market leader in relative humidity measurements, and thin-film capacitive humidity sensors have developed from one company’s innovation into a global industry standard. From humidity sensor to EL-panels and ALD Instrumentarium Oy Search for new challenges Late 1973 ”Humicap” humidity sensor to Vaisala Oy, 1973 1.1.1974 Research unit Request for proposals for new products Vaisala: Investment in IC-technology Pressure sensors Acceleration sensors VTI technologies 1991 Murata Electronics 2012 MEMS research activity, VTT Okmetic The proposal Request for proposals for new products Lecture given on future displays at INSKO Market research: - medical instrumentation, key components I am still confused – but at a higher level … let’s go ahead Let’s develop an electroluminescent flat panel display Thin film technology, sensors, output devices ? ? ? …nobody has done it yet EL ? ? ? ? ? The problem and the solution State of the art: - High performance demonstrated - Major problems with stability due to the high operational voltage Well controlled electronic properties require well ordered material Well order material requires well ordered processing conditions Novel thin film processing technique is needed How about sequential buildup of compounds? May - June 1974 The 1st ALE process for ZnS, September 1974 Hexagonal ZnS: monolayer 3.13 Å n=2.36 Idea of sequential buildup of compounds, June 1974 0.6 mm 1/3 x monolayer 0.4 0.2 Construction of a test equipment 0 0 Optical thickness monitoring 10 20 minutes 320 C 4x10-5 torr 2x10-2 torr 360 C 10-4 torr S Zn 3x10-3 torr 100 C 2 c/s 12.05.2014 12th Baltic ALD, Helsinki 2014 9 Early ALD reactors 1970 1980 1990 2000 EL demos Need, ideas, solution, demonstration, basic patents 2010 2020 Meeting Early ALD the EL reactors target 1970 1980 1990 2000 2010 2020 Picopack Elcoteq Commercial production of EL panels, Lohja Planar Beneq Pilot production of EL panels EL demos Need, ideas, solution, demonstration, basic patents 40 years of ALD reactors 1970 1980 1990 2000 2010 2020 Microchemistry Ltd commercial reactors Research for better understanding of ALD chemistry Commercial production of EL panels, Lohja Planar Beneq Product prototypes, reactors for EL production Need, ideas, solution, demonstration, basic patents 40 years of ALD reactors 1970 1980 1990 2000 2010 2020 2005 Beneq Oy 2004 Picosun Oy Microchemistry Ltd commercial reactors 1999 ASM Microchemistry, commercial reactors & processes Research for better understanding of ALD chemistry Commercial production of EL panels, Lohja Planar Beneq Product prototypes, reactors for EL production Need, ideas, solution, demonstration, basic patents From ideas to global industry 1970 1980 1990 2000 ALE-4 Linz 1996 ACSI 1984 Helsinki University of conferences Technology University of Joensuu 1984 Conference on Solid State Devices and Materials Kobe, Japan 16th Microchemistry Ltd, commercial reactors 2010 2020 Explosive increase in ALD activity - research & industrial 2005 Beneq Oy 2004 Picosun Oy 1999 ASM Microchemistry, of Excellence commercial reactors &Centre processes Research for better understanding of ALD chemistry The European SEMI Award 2004 was handed to Tuomo Commercial production of EL panels, Lohja Planar Beneq Suntola at the Munich Electronics Show 2004 by Stanley Myers, Product prototypes, reactors EL production the President & CEO of SEMIfor (USA) “Honoring the Pioneer in Need, ideas, solution, demonstration, basic patents Atomic Layer Deposition Techniques ... that paved the way for the development of nanoscale semiconductor devices". A Short History of Atomic Layer Deposition: Tuomo Suntola’s Atomic Layer Epitaxy By Dr. Riikka L. Puurunen, VTT Technical Research Centre of Finland, Espoo, Finland riikka.puurunen @vtt.fi FROM MATERIALS PHYSICS TO NANOSCALE DEVICES – 50 YEARS OF FINNISH RESEARCH IN SEMICONDUCTOR TECHNOLOGY Thank you for your attention!